Vertebrata Cuvier, 1812 - vertebrates
   Gnathostomata
     Teleostomi
       Tetrapoda Hatschek & Cori 1896 [Gauthier, Kluge & Rowe 1988]
         Amniota Haeckel, 1866 [Gauthier, Kluge & Rowe 1988] - amniotes
           Class Reptilia Linnaeus, 1758 [paraphyletic] - reptiles
             Subclass Anapsida Osborn, 1903 - anapsids
               Order †Mesosauria Seeley, 1892 [monotypic]
                 Family †Mesosauridae Baur, 1889 - mesosaurs
                   1 Genus †Brasileosaurus Huene, 1931
                   2 Genus †Mesosaurus Gervais, 1865
                   3 Genus †Stereosternum Cope, 1885